Tube bending machine



Nov. 27, 1956 'f-fR, A, SANDBERG 1 BENDING MACHI'N original Fileduuly 1i, 195o 5 shepltus- Isneef 1 Nov. 27, 1956 R. A. sANDBERG,

TUBE BENDING mel-mui:

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Nov, 27, 1956 R. A. SANDBERG 2,7715932 TUBE BENDING MACHINE Drigi,nal Filed July 11,-,1950v 5 Sheets-Sheet 3 Evra-INET 7aay A. Sandberg Nov. 27, 1956 R, A, SANDBER'G., 2,771,932

TUBE Bauamceugcnmv origijngl filed Juiy 11,.. 195o Nov. 27, 1956 R, A, SANDBERG 2,771,932

TUBE BENDING MACHINE l Original Filed 'July ll, 1950 5 Sheetysheet 5 nl QXL L 'g '5% w $1 gg L \I Pu a:

A* il IOS3\\//\M\\j/x j] Z-T/I/E 77227 T Ray A. Sandberg United States Patent TUBE BENBING MACHINE.

Ray A. Sandberg, Waukegan, Ill., assigner to Houdaille- Hershey Corporation, Detroit, Mich., a corporation-.of Michigan Origlnal application July 11' 1950 Serial No. 173,02?. Divided and this application Febinary 26, 1953, senat No. 339,071:

2 Claims. (Cl. 153-67) The present invention relates to a tube bending'machrneand method. M'ore particularly, vthis inventlon deals with a machine and method for winding elongated'v tubing stock into an irregular helicali' form which is' subsequently opened up from its helical form to' a sinuousY tube length adapted for employment` in heat' exchangers` or the like;

In the prior art the formation of sinuous tube lengths for. condensers' or the like has'been` accomplished-'by bending a straight length of' tubingV about spaced and alignedgages and mandi-els, the work' being carried by' a horlzontal table surface', and oscill-ated' or' rotatedV about' a plurality of centers with each' bend: changing its' direct-ion from its former bend by alternating from right to` left to produce' a serpentine sinuous' path ina single plane. Such'rnachines are large, complex', and expensive in manufacture and use -andlimited to-the number of'coils andthe length of coil betweenbends. This is truein all commercial production machines since it is necessaryto-sweep the entire preformed portion of the coil around the mandrel from right to left each timeanother 1180 bend is made.

The present invention now provides a simple form of winding apparatus which is employed tospirally wind an elongated length of tubing about' forming means defining a rotatable Winding frame. The helical tubing coil thus obtained is in the form of an irregular, preferably triangular helix, each bend of which provides'for joining these reaches toone another andto adjacent reaches of the sinuous coil.

More particularly, the rotatable winding frame prefer-ably includes a Winder plate disposed for rotation on a shaft and'- having a plurality' ofV` spaced winding mandrels projecting therebeyond in planes parallel' to the axis of rotation of the plate. Means areV provided` for training an elongated exible length of tubing about the mandrels as. the plate is rotated about its: axis, the tube training or feeding means preferably'y being. screw fed or otherwise advanced along thev axis of rotation ofthe plate to spirally feed the tubing to the- Winding mechanism to'thusl form the helical tubing coil. The` feeding meansv successively contacts the winding mandrels as theV winding-5 plate: is rotated, thereby bending or otherwisedeforming. the'tube about each mandrel in succession. In. this. manner, the feedingmeans advances the tubing alonga themandrels in a. spiral configuration while at' the same time. forming smoothly curved. tubing bends. about each. mandrel. in

turn.

Mandrels are also provided, for expanding the Winder frame orl the mandrels whenthe winding, operation has been completed `to insure the formation of a smooth, geometrical helical coil, and means are also provided for contracting the Winder frame after the coil has been formed' and expanded to facilitate removal of the same from the windingapparatus.

The method of the present invention thus contemplates the' formation of a tubingA coil having an irregular helical configuration, the expansion of'thecoil after' formation toinsure the proper lieiical formation thereof, and tlie- 2,771,932 Patented Nov. 27, 1956 contracting of the coil forming means to facilitate removal of the coil. Of course, the method of the present invention also includes the steps of feeding an. elongated tubing length to a winding frame, advancing the tubing lengths across the face of the frame to obtain a spir'ally wound coil and the maintenance of the winding pressure on the tubing length as itis wound to obtain a uniform coil;

It is, therefore, an important object of the present invention to provide an improved machine. for the formation of a helically Wound tubing coil adapted for expansion into a sinuous tubing length.

Another important object of the present invention is to provide an improved method of forming a sinuous tube length by the winding of the tube' into an irregular helix followed by expansion of the helix to a sinuous configuration;

An additional important object of the present inventionis to provide means for producing axsinuous tube whose overall-V length between ends andthe totalnumber of bends are not limited.

It4 is a' further important object' of the present invention to provide an improved tube bending machine including a winding frame rotatable about an axis, means for feeding a length of tubing to' the' frame for forming an irregular. helical: tubingJ coil thereabout', and means for expanding the tubing coil; after winding is completed tu insure the fonnation'of a smooth, regular' coil'.

Still another important object' of the present invention is'- to provide a tube bending machine' includinga rotatable Winder plate carrying a plurality' of spacedl mandi-els, means` for feeding aV tubinglength about' the mandrels as the plate is rotated, and meansv for advancing the tubing along the axis of rotation of the' plate to form a helical coilof the tubing-'about the'mandrels;

Yet a further important obj'ect of the' presentY invention is-to provide a methodl ofv making a' sinuous tubing, length byl-feeding an elongated lengthv of tubing about a plurality of' spaced mandrel's, advancing-thetubing along the' axial length ofthe mandrels toform a helical coil thereon and subsequently opening up thehelical coil in-to a' sinuous tubing length.

@ther andV further important objects of the present invention. willbeV apparent from theY disclosures in' the specication and the accompa-nying drawings.

On the drawings:

Figure l is a broken plan view of an apparatus of the present invention;-

Figure 2 is a front elevational view of the apparatus of Figure 1';

Figure 3 is an' enlarged. fragmentary sectional view taken along the plane III- IIT of Figure. 1;.

Figure 4' isan enlarged fragmentary pla-nview similar to. Figure l and illustrating the apparatusv having a` coil of tubing wound thereon;

Figure 5. is an enlarged. fragmentary front elevational view showing an. initial loop of tubing disposed"Y thereon;

Figure 6 is a front elevational view similar to Figure 5 illustrating one position of the: apparatus. during thewind mg operation;

Figure V7`is`a greatly enlarged sectional .liewftakenfalong the plane VII-VlLofFigureS;

Figure 8 is a front elevational. view illustrating the apparatus having a formedtubing coil thereon;

Figure. 9l isr a. view similar to Figure 8- illustrating the expansion of the forming maudrels after winding has been completed;

Figure 1.0V is a view.. similar to Figures 8f and 9-' show.- ing contraction of theV winding mandrel; after the: coil has been formed` and immediatelypriol'. to removak of the coil therefrom;

Figure 11 is an elevationalrview of a helically wound Y coil of the present invention;

Figure 12 is a plan elevational view 'of a finishedV Vsinuous `condenser tube made Yin accordance with the sprocket chain 15 lapped about a driving sprocket 16 secured tothe output shaft of a speed reducer 18 driven by a prime mover 17, such as an electric motor or the like. The shaft 13 has secured thereto for rotation therewith a winder plate 20. As best seen in Figure 2, the Winder plate 20-is generally rectangular in outline and has its geometrical center apertured to receive the shaft 13.

The shaft 13 .carries thereon, immediately adjacent the Winder plate, a bell crank 21 which, as best` illustrated in Figure 3, is providedV with a rearwardly projecting boss 22 rotatably disposed on shaft 13. The bell crank is provided with an arcuate upper surface 24 provided with spaced transverse grooves 25-27, inclusive. The boss 22 carries an upwardly extending arm 28 provided with a terminal ange 29 overlying the bell crank surface 24. The arm 28 carries directly beneath the flange 29 a vertically apertured guide block 30 slidably receiving a locking pin 31 having a lower end resiliently urged, as by compression spring 32, into a selected one of the slots 25-27, inclusive. A bell crank actuating arm 33 is secured to that edge of the bell crank opposite the edge 24 to. provide means for rotating the bell crank about the shaft 13 upon lifting the locking pin 31l from thelocking slots or recesses 25-27 of the bell crank.

The bell crank 21 carries oppositely-directed'link arms 34-35 .pivoted to the bell crank, as by pivot pins V36.

VThe arm 35 carries at the free end thereof aV shaft bolt Conversely, upon actuation of the handle 33 in a counterclockwise direction, the winding mandrels will be withdrawn toward one another. The position Vof the slot 25 in relation to the locking pin 31 indicates the furthest Y spreading movement of the mandrels, while the relation between the slot 27 to the locking pin 31 indicates the fully retracted position. Normally-that is, during actual winding operations-the pin 31 is seated in the intervmediate. or operating position slot 26. l0

Again referring to Figure .l of the drawings, the shaft 13 carries, intermediate the bell crank 21 and the journal bearing 12, a sprocket 55 keyed thereto and receiving thereabout a sprocket `chain 56 which is also Vlapped about a sprocket 57 keyed to a shaft 58 journaledwithin Va bearing 59 carried by an upstanding support member 6i) generally parallel to the support member 11 hereinbefore described for the shaft 13. Thus, thel shafts 13 and 5S are geared together for rotation kwith the gearing ratio being determined, as is conventional, by the cornparative sizes and numbers of teethV of the sprockets` 55 and 57. In the illustrated form ofthe .presentinvention, the shafts are driven in a one-to-one ratio.

That portion of the shaft 58 projecting beyond the bearing 59 is threade'rLVas at 61, the threads having a 37 passing throughan arm aperture 38 and through an elongated slot 39 in the plate 20 (Figure 4). The shaft bolt 37 has its head recessed in a cylindrical Vwinding mandrel 40 projecting beyond the front face of the plate 20. A nut 41is threadedly retained on that end of the shaft bolt 37 projecting beyond the arm 35 to secure the arm 35, the shaft bolt 37, and the mandrel 40 into a Vmovable unit.V

The other arm 34 has its free end apertured as at 42 (Figure 7) to receive a shaft bolt 43. The shaft bolt 43 pivotally secures the arm 34 to a pair of links 44 and 45, each having registering apertures 46 therein receiving the bolt. The apertured end of the upper link 44 is recessed, as at 47, to accommodate theV free end of the arm 34, while the lower link 45 is similarly recessed adjacent its apertured end, as at 48, to receive both the apertured'ends of the link 44 and the'arm 34. The links 44 and 45 have secured thereto additionalwinding mandrels 49 Yand 50, respectively, each mandrel .projecting from the same surface of the plate 20 as the mandrel 40 hereinbefore described. Each of the mandrels 49 and 50 'is secured to its link 44 and 45, respectively, by a partially recessed screw 51 threadedly retained by the links and. extending through corresponding elongated slots 53 and 54, respectively, in the plate 20.

It will be seen that upon manipulation ofthe handle lead which is correlated with the remainder of the apparatus as will be hereinafter more fully described. The shaft 58 supports thereon a pressure bar 62 extending radially from the shaft toward the Winder plate 20 and carrying on its undersurface a feeding guide 63 having a lower downwardly opening elongated Vslot 64 best illustrated in Figure 7. Thatrend of the pressure bar 62 overlying the shaft 58 is provided with a lower Vfeeding Vblock 65 having an open bottomed arcuate topped slot 67 therein provided with an interior thread 68 in threaded engagement with the threaded portion 61 of the shaft 58. v

, It will be seen that, upon rotation of the shaft 58, thebar 62 andthe feeding guide 63 will be advanced along the length of the shaft 58 which is parallel to shaft k13 upon which the -plate 20 is disposed. The feeding guide 63 abuts one or more vof the Vwinding mandrels 37, 49 and 50 at all rotating positions of the plate 20. It is desirable to taper that end 69 ofthe feeding guide remote from the shaft 58 in order to in-I sure smooth feeding of thek tubing about the extreme mandrel 40, as will be hereinafter described, Yand also to insure smooth contact of this end of the feeding guide with the winding mandrels. Y

It will be noted, particularly in Figures 2 andl 7 of the drawings, that the face of the plate 20 from which the winding mandrels 40, 49 and 50 project is provided with an elongated tapering groovev 70 extending in a straight line from the undersurface of the winding mandrel 49 to the undersurface of the winding mandrel 40, the depth of the groove decreasing progressively from the mandrel 49 to the mandrel 40 and vanishing at the mandrel 40 for a purpose to be hereinafter-more fully described. A clamping plate 71 is secured by a suitable Y means, as by a bolt or screw 72, to the same surface of the plate 20 to overlie a portion of the groove 70.

The operation of the apparatus hereinbefore described will be appreciated in Figures 4-10 of the drawings. To initially start the tube winding operation, a substantially straight tube length is trained about a mandrel 40 with the free end 81 of the tube length being positioned with the groove 70 and the extreme free end of the tube underlying the mandrel 49 and projecting'beyond the corresponding end surface of the Winder plate 20, After the free end 81 of the tube length is positioned in the groove 70, the Winder plate 20 is rotated from its initial position in the direction of the arrow shown in Figure 5. In the initial position, the mandrel 40.is at the right as Vviewed in Figure 5, mandrel 50 is intheA upper left and mandrel 49 is in the lower left. From this initial position, rotation of the` shaft'13 through 180 in the :arrasa-a direction of the arrowiii-Figure 5' bends the tubing about the mandrel 40 and into the-shape shown in Figure 5.

Thatportion- 8-1VV ofthe tube 80- which is positioned Witliinthe groove 70 (Figure 7')I islaterally displaced outside a vertical projection -oftheA extreme ends of the pressure bar 62 andof the feeding guide 63, while that portion 83 of the tubing length 80' lapped about the mandrel 4i) direct-ly underlies the feeding groove 64 of the feeding guide 63. The reachv of the tube 80 extending between the mandrels 40 and? 49 and overlying the same is-'positioned wit-hin the. groove 64, the pressure bar maintaining the feeding guide 63 in contact with the mandrels. Upon rotation of the plate 20 in a counter-clockwise direction, as indicated by the' directional arrows of Figures 5 and' 6, it will be seen, that the pressure bar 62' and the feeding guide 63 ride about the periphery ofthe mandrel' 49 until' the' position of Figure 6 is attained in which' the feeding guide' 63 contacts both the mandrels 49 and 50. Thus, the pressure bar smoothly deforms the tubing into surface contact with the mandrel 49, forming a smooth joining curve about a portion of the periphery thereof.

Upon further counter-clockwise rotation of the plate 20 about the shaft 13, the pressure bar 62 will be lowered with the feeding guide 63 maintaining contact with the mandrel 50 until the feeding guide contacts the mandrel 50 and the mandrel 40. Upon further rotation, the feed guide will contact the mandrel 40 until the position shown in Figure 5 is again realized, thus completing a single revolution of the plate 20.

It will be understood that the feeding guide 63 of the pressure bar 62 is advanced axially along the threaded portion 61 of the shaft 58 as this shaft is rotated in conjunction with the shaft 13 of the plate 20 by virtue of the hereinbefore described sprocket and chain feed arrangement. The axial advancement of the bar 62 of the feeding guide 63 upon one rotation of the shaft 58 is preferably equal to approximately the outside diameter of the tubing 80, so that a spirally wound relatively tight tubing coil is formed upon continued rotation, as illustrated in Figure 4. It Will be appreciated that the slot 70, by laterally displacing the terminal portion 82 of the tubing 86 from its position underlying the pressure bar and feeding guide, will prevent interference of this portion of the tubing during the initial winding operation .and before axial advancement of the bar and guide has been realized.

Counter-clockwise rotation of the plate 20 is continued until a desired length of tubing has been wound about the mandrel, or until a coil of the desired number of superimposed turns has been built up. In the manufacture of a ten-pass refrigerator condenser, for example, Winding is continued While the plate 20 passes through four complete revolutions, at the conclusion of which the plate 20 is in the position illustrated in Figure 8 and the tubing S0 is severed, as at 84 in Figure S. Alternately, the tubing may be cut to a predetermined length before winding is initiated, so that severance after winding is unnecessary. Of course, in order to sever the tubing, the bar 62 and the feeding guide 63 are removed from contact with the tubing 80, and while so removed, the terminal tubing portion S4 is deformed downwardly relative to the plate 20 to the position indicated in dotted outline in Figure 8. In this dotted position, the tubing terminal portion 84 extends from the mandrel 40 to overlie the mandrel S0, `the tubing portion 84 thus overlapping or crossing the first free end S2 of the tubing 80 and each of the superimposed short runs 94 of the coils.

Inasmuch as the complete coil 86 of tubing has been formed, it is now desirable to expand this coil to insure a tight symmetrical formation of the coil about the mandrels. This stretching is accomplished by removal of the locking pin 31 from its position within the central slot 26, Within which it has been positioned during the ing the coilV from the center thereof. toinsure the forma-'2,V

tion of straight runs. between the mandrels.

Next, to removethe: coil 86 from its position about.

the mandrels, the mandrels are contractedi by actuating' the handle 33, after: removal of' the. pin 31A from; the. position within; theI slot 25,.,so'Y as to. bringthe. slot. 27 into registry with the locking p i'n. While the. bell crank' 21 is in this; position, the pressure barv and:V guide are again elevated: and the coil is: simply removed. from-the: retracted mandrel.

The coil which is thus formedV comprises an irregular, preferably triangular, helix defined by straight tubing runs between curved tubing joiningportions, the continuous coiled tubing length being spirally wound by virtue of the advancement of the feeding guide during rotataion. As more particularly illustrated in Figure ll of the drawings, the finished coil 86 comprises elongated straight runs 91 and 92 joined -at one end by curved portion 93 and at the other end by a short run 94. The free ends S2 and S4 are joined to the terminal bend of the coil by the curved portions 93 thereof. The triangular helical coil thus formed is compact and small in overall size to facilitate handling and/ or shipping during or prior to subsequent formation of the sinuous tubing length.

Upon opening or spreading the coil, the configuration of Figure l2 is obtained in which the runs 91 and 92 are parallel with the short runs 94, being aligned to form joining portions between the runs 91 and 92 of the same' turn, and the curved portion 93 joining the runs 91 and 92 of adjacent overlapping turns of the helical coil as originally formed.

As shown in Figure l2, the end 82 overlaps the short straight run 94 of the initially formed turn, while the terminal end 84 underlies the short reach 94 of the last formed turn, the end portions 81 and 87 also being parallel to one another and to the runs 91 and 92 hereinbefore described.

It Will be seen that the end product prepared by the use of the apparatus hereinbefore described is a sinuous length of tubing Well adapted for attachment to a heat exchanger plate to form a plate-and-tube type heat exchanger, such as that described in my pending application for patent, Serial No. 81,970, filed March 17, 1949, now Patent No. 2,660,412 issued November 24, 1953, and assigned to the assignee of the instant invention.

The present application is a division of my co-pending application Serial No. 173,083, filed July l1, 1950.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In a winding apparatus, an elongated winder plate, a first mandrel carried at one end of said Winder plate on one side thereof, second and third mandrels carried at the opposite end of said Winder plate at said one'side thereof to define with said first mandrel and said Winder plate a generally triangular winding frame, said Winder plate having a groove of increasing depth extending from one side of said lirst mandrel along said Winder plate to a position between said second and third mandrels, and means for winding tubing or the like on said mandrels with one end of the tubing or the like extending in said groove and with the adjacent portion of the -tubing or the like extending around the mandrels in close relation to said Winder plate, the depth of said groove at the end thereof between said second and third mandrels being sufcient to accommodate the end of the tubing or the like in laterally displaced relation to succeeding turns of the' Ytubing or the like on the mandrels.

,2. In a winding apparatus, an elongated Winder plate, a rst .mandrel 'carried at one end ofA said Winder plate on one side thereof, second and third' mandrels Vcarried at. the opposite endV of said WinderY plate at saidoneY sidethereof toV dene withV saidv first mandrel and said fwinder plate a generally V'triangular winding frame, said Winder plate having means on said one side thereof for positioning an initial length Yof tubing or the like'to 'extend from betweensaid second and third mandrels and around said first mandrel, and means Vfor Winding tubing or the like on said mandrels with said initial length of tubing .or the like positioned byr said means and with vthe adjacent portion `of the tubing or the like extending around themandrels in close relation toV said Winder plate.

References Cited in the le of this patent fUNiTED STATES PATENTS Gibbs Jan. 16, 1817Y Germany Oet. 14, 

